Powerful earthquake strikes Idaho, United States

A M 6,5 earthquake struck Idaho, United States on Tuesday, March 31, 2020.

According to the U.S. Geological Survey (USGS), the seismic shock occurred at 5:52 pm and its epicenter was located about 116 kilometers northeast of Boise, the capital city of Idaho State.

The temblor struck at a relatively shallow depth (10 km) and originated at a complex strike-slip fault in the crust of the North America tectonic plate. It was the most powerful shock to hit the region in decades. In particular, all earthquakes that have occurred in a 50-kilometer radius around the event in the past 50 years have been less than M 5,0. A massive M 6.9 seismic shock had occurred in Idaho back in 1983 resulting in 2 fatalities and severe infrastructure damage.

The earthquake was felt as far as Salt Lake City in Utah and Helena in Montana, but fortunately, there are no reports about extensive damage or injuries. Some ground failures were triggered and mostly affected roadways in the region.

Brett Woolley, the owner of a restaurant in the town of Stanley, said that the powerful shock was preceded by an intense sound. “I heard the roar, and at first it sounded like the wind but then the roar was tremendous. The whole house was rattling, and I started to panic. I’m sitting here perfectly still and the water next to me is still vibrating,” Woolley, stated.

Aftershocks followed the main event, with the greatest being M 4.8 but no severe issues emerged.

The shock could have caused major problems in health facilities that are under high pressure due to the coronavirus pandemic outburst that has significantly impacted Idaho. Marcus Smith, a coordinator of emergency room units at St. Luke’s Wood River Medical Center, located 104 kilometers from the epicenter of the quake, stated that the shock did not affect the everyday procedures at the hospital. 

According to Glenn Thackray, Professor at the Department of Geosciences at Idaho State University, the earthquake was not unexpected. In fact, Prof. Thackray had warned people about the possibility of a large earthquake hitting the region since 2010 when he discovered a 64-kilometer east-dipping normal fault near Stanley. Nevertheless, this was not that fault that produced the current shock. “We knew quickly that that area was likely to have earthquakes. I was able to tell people up there (in Stanley) the common-sense things to do,” Prof. Thackray said.

Click the video below to watch footage from the moment of the earthquake's impact.